The present invention is directed to an apparatus for controlling digital driver signals to accommodate parametric requirements of a host system. Specifically, the present invention is directed to an apparatus for controlling output of a digital driver circuit, which apparatus is adaptable to accommodate parametric requirements of a host system in one of two general situations: (1) a requirement for fast transitions of the driver signal, and high direct current (DC) at the pad to which the driver signal is applied is not required, and (2) slow transition of the driver signal is desired with high DC requirements at the pad.
Fast transitions of driver output generate undesired electromagnetic noise in circuitry so that the preferred embodiment of the invention to accommodate situation (1) above further provides an increase in output impedance, seen from the pad, upon completion of the transition of the driver signal in order to effectively damp any noise which may have been caused by the fast transition occasioned by the apparatus.